Duplicating mechanism



May 9, 1 944. n c gf I 2,348,280

nurucnme MECHANISM 3 Sheets-Sheet 1 Filed Feb. 15, 1941 y 1944 '1'. F. BRACKETT 2,348,280

' DUPLICATIN-G MECHANISM Filed Feb. 13, 1941 3 Sheets-Sheet 2 w fi. I Gttornegs May 9, 1944. '17. F. BRACKETT 3,348,280

' DUPLIOA'IING MECHANISM Filed Feb. 13, 1941 3 Sheets-Sheet 3 zan wfimc keza Patented May 9, 1944 Tracy 'F. Brackett, Detroit, Mich., assignor to General Motors Corporation, Detroit, Mich, a

corporation of Delaware Application February 13, 1941, Serial No. 378,707

tus to be described. A similar smaller frame 4 Claims.

This invention relates to contouring apparatus and more specifically to means for reproducing a given surface by controlling a movablev cutting means from other means following a templet or model and is a continuation in part of my application Serial No. 156,644, filed July 31, 1937, in the name of Tracy F. Brackett, entitled "Photocell control for die-sinking machine," whichhas become Patent No. 2,242,506, issued May 20, 1941. In that application there is disclosed apparatus for reproducing a model by, having a sensitive tracer headwhich is continuously fed over the surface of said model control the position of cutting meanswhich at the same time is continuously fed over thesurface of a blank. However, in having such a construction inwhich, letfus say, one side of an automobide body is' reproduced at a time, it would be necessary to'reverse the model and then proceed through thesame tracing procedure to obtain the opposite or complementary side of the body for the complete article.

It is therefore an object of my invention to provide means whereby both complementary sides of a model, if it is symmetrical, are reproduced at onetime.

It is a further object of my invention to provide means whereby a complete symmetrical ar-' ticle may be reproduced from a model at one time by merely tracing one side of the same.

With these and other objects in view, the em bodiments of my invention will be best understood by reference to the following specification and claims and the illustrations in the accompanying drawings, in which:

Figure "I is a front elevation of a device for reproducing asurface according to my invention; Figure 2 is a top plan view of the apparatus; Figure 3 is an enlarged detailed view showing the clutch and driving mechanism controlling the drive for the cutting means taken on line 3-3 of Figure 1;

V Figure 4 is a sectional view taken on line 4-4 of Figure 3;

Figure5 is an enlarged detailed section of the.

coupling means used in the driving shaft; and

Figure 6 is a sectional view taken on line 6-6' of Figure 5.

Referring now specifically to Figure 1, there is shown therein a large rectangular stationary frame composed of longitudinally extending base members 2, cross members 4, vertical uprights 6 and top longitudinal members 8 braced byupper cross members l0. 'I'hisforms a large rectangular box frame for supporting the various apparacarry directly 'above them a pair of upper longitudinal members 14 which are secured to the lower. members by vertical rods 16. This construction provides a smaller box frame member within the larger stationary box frame member and supported on a plurality of roller members such as H! mounted on the upper and lower track members 2 and 8 of the stationary frame. Longitudinallyextending movable members I 2 and M are formed of T beams with their base portions,

mounted to ride between a pair of rollers 20 sup ported on the mechanisms, 18. Thus the movableframe may move back and forth longitudinally within the large stationary box frame.

To one side of the base portion of the movable frame is rigidly secured an internally threaded sleeve 22 through which a long threaded rod 24 is positioned, the end of said rod being secured to a bevel gear assembly within the housing 25 which transmits motion to a rod 28 at right angles thereto which rod is connected to a suitable driving means located within the housing 30. The detail of this drive forms no part of this invention and therefore will not be described specifically except to say that when the same is energized from the tracer head and causes the shaft 28 to rotate, the threaded rod 24 will, of course, be rotated and through the threaded sleeve 22 cause the movable frame tomove longitudinally with respect 'to the stationary one. This apparatus is'duplicated .on the opposite side of the machine l model suchas shown indotted outline and mounted upon a suitable stationary support 38 and as the same is fed thereover to operate the control mean 311 to feed the movable frame back and forth as required by the contour of the body. The body or model 36 may be scanned either vertically or horizontally and when vertical scanning is desired a vertical threaded rod 40 is driven, said rod passing through an internally threaded sleeve 42 rigidly secured to the tracing mechanism to cause the same to move up or down, depending mechanism.

upon the direction of rotation of the rod. This rod 48 is driven by geared connections 44 and associated rod 46 to a driving means 48 similar to the drive mechanism 38 already mentioned, the drive in this case, however, being constant to provide scanning and not intermittent as in the case of means 38.

The tracing mechanism embodies means energized upon a slight movement of the tracer head in either direction from a neutral position which energization is then amplified by an amplifierj 58, the resultant current passing then to the. dI'iVv ing mechanism 38. Thus if the driving means 48 is energized and the tracing point is, placed at the lowermost extremity of the model as the same feeds upwardly over the surface due to the rotation of the threaded rod 48, the contour will cause energization of the driving means 38 in either direction and cause the movable frame to move back and forth. Instead of scanning the,

may be scanned horizontally a threaded sleeve such as 52 the tracing means engages a long threaded rod 54 whose rotation causes the tracer assembly to move back and forth across the frame. This rod 54 .is in turn driven by gear model vertically it and in such case rigidly secured to means 58, rod 58 and driving means, 68 similar ing the cutter head. A threaded sleeve, portion 68 engages a long threaded rod 68 which will cause the cutter mechanism to move vertically. This rod Wis-connected to the previously mentioned driving member 48, through certain force transmitting means I8 50 that as the tracer is driven vertically up over the model the cutter will also be moved up over the blank which it is cut-- the vertical support 64 is also carried by the movable frame, as this frame is moved slightly longitudinally due to the tracer energizing the driving means 38, the cutter will of course reproduce on the surface such motions and therefore in toto the blank will eventually have reproduced thereon the surface that the tracer head is moving over. I

As in the case of the tracer, of course there is also provided a transversely-extending threaded rod 172 which engages a threaded sleeve I4 for moving the cutter head across the apparatus or machine instead of vertically with respect thereto. This threaded rod is connected, as would be expected, to ashaft 16 which is directly connected to and driven by the driving means 68 which also drives the transverse threaded rod 54 of the tracer ting. Since However, the connection between thev threaded rod l2 and the shaft driven in either direction. This mechanism is best. shown in detail in Figure 3 in which the rod I2 is shown journalled in a suitable bearing 18 which is supported on the stationary framememberand carries on its innermost end a beveled gear 88 which is secured to the shaft. 12 by a pin 82 diametrically placed through the shaft and gear. Shaft I6 however extends directly from of the blank any. of

I6 is through a reversible clutch means so that the mechanism may be the driving mechanism 88 into a block 84 having a central aperture to receive the same and is secured therein by a pin 86 which extends diametrically through the shaft and through a corresponding opening in the block 84. This block 84 has on the two opposite faces a rectangular groove within which is mounted a pair of bars 88 and 88 and secured therein by plates 92 and 94 which are bolted thereto. The bars 88 and 98 are considerably longer than the block 84 and,

as shown in Figure 5, extend out to the right.

The mounting pin 86 also passes through the bars to maintain them in place.

Mounted next to the first block 84 is a similar block 84' which has the same central opening for a shaft 96 which is supported in alignment with shaft 16' and secured by a pin 88 which projects through the block 84 at right angles to the pin 86 which extends through the block 84. The block 84 has the same grooves in the upper and lower surfaces and the bars 83 and 98 extend through these grooves and are held against the sides of the block by plates 92 and 94'. The pin 98 in this case, of course, does not pass through the bars. It will thus be evident that the two shafts l6 and 96 may move axially of each other but rotate together through this connection inasmuch as one shaft is pinned to the two longitudinally extending bars and the other shaft merely pinnedto the block which may move longitudinally on the bars. In this way I provide a means for allowing the shifting of the driving means from one direction to the other by moving the shaft 96 longitudinally but still retaining the driving connection from shaft 16.

Shaft 96 extends through a suitable bearing I88 which is supported in the frame member I8I so that thesame may move axially therein but trunnion the shaft in any position within a reasonable limit, and adjacent the inner end of the bearing there is mounted a beveled gear I82 which. ispinned to the shaft by pin I84. Mounted in spaced relation to the first beveled gear and on the opposite side of the shaft I2 at right angles thereto is another beveled gear I86 also pinned to the shaft 96 by a pin I88. Shaft 96 then passes through a second bearing member [ID which is also slidably mounted in a circular opening III in the supporting means H8 and continues on to additional driving means.

Supported on the under side of the housing which includes all of the gears just mentioned is a lever II2 which extends substantially parallel to the axis of the shaft I2 but may be moved from one side thereof to the other as shown in Figure 3 in the full and dotted line position. This lever H2 is spring biased to either side by a spring II4 whose position may be changed and is also connected to a transverse lever I I5 which lies directly underneath the shaft 98, the two being pivotally pinned together by a bolt H6. This lever extends from the lever I I2 out to a position underlying the slidable bearing II8 which supports the right hand end of the shaft 96 as shown in Figure 3 and a pin member II8 connects the end of lever II 5 with the bearing member II8. Thus as the lever H2 is moved back and forth the shaft 96 through this lever and pin connection will be moved as shown by the various dotted line positions to move either beveled gear I82 or I86 into engagement with the beveled gear 88 to drive shaft I2 from shaft 96. This change from onedriving means to another will, of course, reverse the direction of rotation of the shaft I2.

the purpose of which will soon become evident as the description proceeds.

This housing is shown at I on FigureZ and there is also a duplicate housing of the same character mounted at I22 for driving a similar transverse rod I4 to carry cutter mechanism over a similar blank surface I24 which is supported on the end of the frame in exactly the same manner that the other blank I26 is supported which cooperates with the first mentioned cutter. A coupling I similar to 8484' is also incorporated in the shaft.

It will thus be evident that as the driving means 60 feeds the tracing head 34 across the surface of the model, at the same time there will be fed two cutter means, namely, I28 and I30, in the same or opposite directions, as desired, over the surfaces of two blanks. The cutting mechanisms will be corrected in their position to follow a duplicate contour of the model by the tracer head movement through driving means 30 and thus from a single tracing we may produce either a. plurality of halves of the same complementary contour or two opposite halves to form a complementary whole if the devices are adjusted so that the cutter means travels in opposite directions. Thus we can obtain from one side of a car body two opposite sides and furthermore they will be identical and not subject to any inaccuracies such as would appear if the original model were scanned first on one side and then on another. It is thus obvious that I have provided means for producing by a single scanning action the two complementary halves of a symmetrical object.

I claim:

1. In duplicating mechanism, a stationary frame upon which may be mounted a model and a plurality of blanks in spaced relation, a movable frame supported thereon, a tracer head and a plurality of cutter heads mounted upon the movable frame associated with the model and blanks respectively, means for moving said tracer and cutter heads simultaneously across the surface of the model and blanks respectively, one of said cutter heads traveling in the opposite direction to the other, and means controlled by the tracer head to move the movable frame normal to the model to maintain the tracer in light contact upon the model surface and move the cutters to generate the model surface, one cutter producing one half of the model and the other the complementary half with a scanning of only one side of the model.

2. In duplicating mechanism, a stationary support upon which may be mounted a model and a plurality of blanks to be cut, means for mounting said model and blanks in spaced relation on the support, a member mounted for movement with respect to the support, a tracer head and a plurality of cutters carried thereby in juxtaposition to the model and blanks respectively, means for driving said tracer head and said cutters simultaneously over the surfaces of the model and blanks, one of the cutters traveling in the opposite direction to the other and to the tracer head and means controlled by the tracer head to move the movable member in a plane normal to the surfaces of the model and blanks to correct for the contour of the model and so move the cutters that they will reproduce the model surface on said blanks, one of the reproduced portions being complementary to the other.

3. In duplicating mechanism, a stationary frame upon which may be mounted a model and a plurality of blanks in spaced relation, a frame movable in a plane normal to the surfaces of the model and blanks, a tracer and a plurality of cutter heads mounted upon said movable frame in juxtaposition to the model and blanks respectively, means for simultaneously driving the tracer and cutter heads with respect to said frame to scan the surfaces of the model and blanks, and reversing means whereby a part of the scanning means may be driven in a reverse direction from the remainder.

4. In duplicating mechanism, a stationary frame upon which may be mounted a model and a plurality of blanks in spaced relation, a frame movable in a plane normal to the surfaces of the model and blanks, a tracer and a plurality of cutter heads mounted upon said movable frame in juxtaposition to the model and blanks respectively, means for simultaneously driving the tracer and cutter heads with respect to said frame to scan the surfaces of the model and blanks, and reversing means in the driving means to the cutter means whereby either or both of the cutter means may travel in the same or opposite scanning directions to that of the tracing means.

TRACY F. BRACKETT. 

